This work consists of two volumes, an introduction to the writing commonly called Barlaam et Ioasaph, and a critical edition of the Greek text. The text edition (vol. 2) was published in 2006, the introduction (vol. 1) only two years later, in late 2008. It was decided to review the text edition together with the introduction; hence the delay of the review of volume 2.

In the centuries around the beginning of the common era, both oral and written stories about the life and teaching of the Buddha circulated in South-Eastern Asia. After their spread from India into Tibet, they were taken further westwards by Buddhist missionaries who travelled into Central Asia, where Manichaeans (well-known for their eclectic adaptation of elements from older religions) found great affinity between their own faith and this Buddhist message. They adopted and adapted the stories of Buddha's life and teaching by adding quite a number of ascetic features but also some Christian elements. In a still later stage, this Manichaean propaganda document reached Baghdad where an Arabic version came into being with the title Bilawhar wa-Yudasaf (= Budhasaf = Bodhisatwa; note that in Arabic the B and Y are written identically). The name Bilawhar, the teacher of the Buddha in the Arabic version, reappears in the first fully Christianized version of the Buddha story, the so-called Balavariani, made in Christian Georgia (Caucasian Iberia); his pupil is called Iodasaph there; Balavar was later garbled into Barlaam. This Georgian text was the missing link between the oriental Buddhist legend and the Greek Christian text called Barlaam et Ioasaph, until the Georgian version was discovered some 50 years ago. The Georgian Balavariani was translated into Greek (and much embellished again) around the year 985 by a Georgian monk who did much translation work from Georgian into Greek and from Greek into Georgian in a monastery at Mount Athos, namely, Euthymius the Hagiorite (= the man from the Holy Mountain), who lived from ca. 955-1028. Since some of the manuscripts state in a preface that the story was brought from east to west by a certain John from the monastery of Saint Sabas in the Judaean desert, it was soon believed that the most famous John of this monastery, John of Damascus, was the author. This ascription is found for the first time around 1100 and John's authorship remained undisputed for many centuries, but that position is now rarely defended. When decades ago the monks of the Abbey of Scheyern planned a new critical edition of all works of John the Damascene, they still took this work to be from his pen and Volk's predecessor as editor, B. Kotter, decided to include it, but Volk, who took over Kotter's task after the latter's death, unwaveringly puts the word 'spuria' on the title page, and rightly so.

Volk's two volume magnum opus puts the study of this curious Byzantine piece of hagiography that started its life as a Vita of Buddha on a completely new footing. The first volume, the Einführung, begins with a detailed and magisterial survey of the history of theories about the author of Barlaam et Ioasaph and Volk demonstrates why the ascription of authorship to Euthymius the Georgian has now become unavoidable. Then follows a long chapter on the sources used by the author, among which the most important are, apart from the Buddha legend in its Georgian dress and the Bible, the Vita of Mary the Egyptian (by Pseudo-Sophronius), the Narratio of Pseudo-Nilus Ancyranus, the so-called Eklogai of John Chrysostom (selections from his homilies compiled in the tenth century), the second-century Apology of Aristides, and the 'Fürstenspiegel' of Agapetus Diaconus. The various ways in which these sources are used and reworked are presented here. A short but fascinating chapter deals with the reception history of our document up until the end of the twentieth century (it contains among other things the bizarre story of how Catholic missionaries in the early modern period used Barlaam and Ioasaph in their efforts to convert Buddhists in Asia to Christianity). The next chapter ("Der Inhalt", 158-239), long though it is, is a shortened and paraphrastic rendering of the contents of the story. This is a useful tool for the reader who wants a quick orientation in the work as a whole or in certain chapters, but it would have been more user-friendly to place this chapter earlier in the book.

The pièce de résistance of the book is a chapter of more than 250 pages in which Volk discusses the textual tradition of Barlaam et Ioasaph. Here one finds an impressively detailed list and exhaustive description of all Greek manuscripts of the work known today. There are more than 160 of them, of which 36 are from monastery libraries on Mount Athos (where the Greek text came into being) and 32 in the Bibliothèque Nationale in Paris. It is striking that the oldest manuscript is from 1021, no more than 35 years after the work was written and copied during the lifetime of Euthymius. Volk divides the manuscripts into five families and presents a detailed stemma codicum at the end of the book on a fold-out sheet. All of the manuscripts have been personally inspected by Volk, a truly immense labor. Hereafter he deals with translations of the text, ranging from the first Latin one from 1048 and the earliest Arabic one from 1065 to the most recent twentieth-century ones into a variety of modern languages including Modern Greek. The final chapter ('Die Illustrationszyklen') does not deal with the miniature illustrations in several of the manuscripts themselves but with the explanatory captions accompanying them. The Greek text of all these captions (almost 400) is presented in full, even when the illustration itself is lost, as is often the case. So far on the 'Einführung,' a most impressive feat.

The final result of all this labor is found in vol. 2, the critical edition. To make clear how gigantic a step forward this is compared with other editions, it should be compared to the currently most used edition, that by G.R. Woodward and H. Mattingly in the LCL, first published in 1914 and reprinted up till the present day. Woodward and Mattingly reprint the text as it was constituted by J.F. Boissonnade in his Anecdota Graeca of 1832, the first complete edition of the Greek text. Boissonnade knew only a handful of manuscripts, but his text gained authoritative status because it was included in Migne's uncritical Patrologia Graeca. Boissonnade nonetheless had a very limited and selective critical apparatus, but Migne omitted it, and so do Woodward and Mattingly. Volk's very complete critical apparatus fills on average half of every page. His text differs in many hundreds of instances from Boissonnade and the LCL edition. In those instances where I checked the manuscript basis of these differences it was always easy to agree with Volk's editorial decisions. His text is an exemplary demonstration of common sense and acumen.

The edition is followed by some 100 pages that are equally divided between Appendices and Indices. The appendices contain Greek Epitomai and excerpts of selections (esp. the parables) from the text of Barlaam et Ioasaph, most of them from one and the same manuscript. The indexes cover biblical quotations and allusions, non-biblical quotes, testimonies (later medieval texts that quote Barlaam et Ioasaph), and a select index of the most important Greek terms (a full concordance would perhaps have been better). All of this is carried out with very great akribeia -- I have found not even one error in the Greek spelling or accentuation. This work is a paragon of diligent and meticulous scholarship.